The present invention relates to torque transmission units which convey torque from a motor to rotating paddles in cooling chambers that produce partially frozen beverages.
A partially frozen beverage is produced by continually agitating and cooling a carbonated beverage contained within a cooling chamber. The beverage is continuously agitated by rotating paddles in order to keep the beverage in a partially frozen, semi-solid, semi-liquid state.
In order to achieve and maintain the consistency of the partially frozen beverage, the flow of refrigeration coolant to and from the cooling chamber is regulated by a feedback control mechanism. One type of feedback control mechanism senses the counter torque exerted on the paddles by the partially frozen beverage in the canister. As used herein, rotational movement and torque is delivered to the paddles by a motor and various drive and transmission mechanisms in one direction. The beverage resists this motion and exerts a counter torque on the paddles. This counter torque increases as the beverage freezes. The counter torque is conveyed through the drive mechanism back to the motor. U.S. Pat. No. 4,093,055 to Blackburn et al. describes a torque transmitting, torque sensing system. The description of the system in Blackburn et al. is incorporated herein by reference thereto.
Blackburn et al. disclose a motor coupled by a pair of belts to first and second torque transmitting units. In one embodiment, the torque transmitting units each have an axially separable coupling unit. The torque is transmitted from the motor, through the belts, to each torque transmitting unit. Each unit has an output pulley wheel that drives another belt extending around a pulley wheel attached to the shaft upon which the paddles are mounted. As the counter torque developed by the partially frozen beverage increases, the axially separable coupling members separate. Blackburn et al. disclose a switch that monitors the axial separation of the coupling members. The switch is activated when the coupling members are separated a predetermined distance. A control mechanism is then activated and the flow of refrigeration coolant to the cooling chamber is stopped. Since the partially frozen beverage is no longer being chilled, the beverage does not solidify further and the appropriate consistency of the beverage is achieved. By sensing further changes in the counter torque of the drive system, a feedback control system is established that controls the flow of coolant to the chamber and hence the consistency of the beverage. U.S. Pat. No. 3,108,449 to Lents describes such a partially frozen beverage system. U.S. Pat. No. 3,823,571 to Smith et al. also discloses a partially frozen beverage system. The disclosures in Lents and Smith et al. are incorporated herein by reference thereto.